To inaugurate trolleybus operation Pontypridd bought seven six-wheel single-deckers from English Electric. These had the SD6WTB chassis and English Electric’s own B32C bodies and all entered service on 18th September 1930 with the opening of the trolleybus system.

The trolleybuses were numbered in a separate series from the motorbuses and these vehicles were given fleet numbers 1 to 7. The registrations were slightly more complex, presumably because Glamorgan as issuing authority had a policy as in some other areas where odd and even registrations were issued to different classes of vehicle. Hence 1 to 7 were registered TG 379/81/83/85/87/89/91.

Rebuilding work resulted in a variety of changes, the most visible of which were the removal of the nearside cab door and the replacement of droplight ventilators with half-drop units.

The new fleet of Karrier Ws rendered these single-deckers obsolete and they were withdrawn in 1946 and 1947. Cardiff had an urgent need for single-deck trolleybuses and following inspection agreed to buy the whole batch, provided Pontypridd completed some outstanding modification works. Once Cardiff’s new single-deck trolleybuses arrived in 1949 these vehicles were no longer needed and the last was withdrawn by August 1950. All went for scrap.